As the title says I have problems with the driver after updating to 12.04. The GUI doesnt start anymore, I only see the terminal. I have googled this for a couple of days now and have tried different things like running commands for update, upgrade and tried to uninstall and re-install the NVIDIA-drivers but with no success.

No matter what I do I get this message:
"Error: API mismatch: the NVIDIA kernel module has version 295.40, but this NVIDIA driver component has version 295.49. Please make sure that the kernel and all NVIDIA driver components has the same version."

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If you have used the .run file from nVidia's website

then go to a console by pressing Alt+Ctrl+F1 and then run nvidia-xxx-pkg1.run --uninstall to remove the previous driver components. Now give a reboot and see if that works. If not, then execute sudo echo "blacklist nouveau" >> /etc/modprobe.d/blacklist.conf so that the default nouveau driver for nVidia chipsets are not loaded instead of proprietary one. Finally install packaged binary drivers by sudo apt-get install nvidia-current-updates-dev.

I actually think that I installed it manually from the .run file but I tried the commands and rebooted the computer. The GUI came back but I can strangely enough only log-in with a guest-session. When I try to login with my username and password (which is correct!) the screen turns black and the NVIDIA logo flashes for a short while and then I am back on the log-in screen.
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patlanJun 2 '12 at 12:51